Pneumatic Seed Delivery System

ABSTRACT

A pneumatic seed delivery system is provided for use with planter for row-crop planting an agricultural field in which the pneumatic seed delivery system may use high pressure air to accelerate seeds that are singulated from a seed meter to match ground speed when planting. The pneumatic seed delivery system includes an air accelerator arranged downstream of a release location of the seed meter. The air accelerator may define a pneumatic device such as an air conveyor or air amplifier that merges a primary airflow with a controllable supplemental airflow to provide a correspondingly controllable combined airflow that carries and accelerates the singulated seeds so that the seeds can be released with a rearward horizontal seed velocity component that approximates a forward ground speed of the planter to reduce seed tumble.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional of application Ser. No.15/499,341 filed Apr. 27, 2017.

FIELD OF THE INVENTION

The subject matter disclosed herein relates generally to row-cropplanters and, in particular, to a pneumatic seed delivery system forcontrolling seed delivery velocity of planters.

BACKGROUND OF THE INVENTION

Modern farming practices strive to minimize operating expenses. One wayof reducing operating expenses is to operate the farm equipment atrelatively faster speeds, which reduces the amount of operating time tocomplete certain tasks. When operating equipment at faster speeds, itcan be important to maintain the quality of operation that can beachieved while operating at relatively slower operating speeds.

This can be especially difficult to accomplish during plantingoperations that require precise seed depth placement and spacingaccuracy in order to maintain a good seed environment. Accordingly, seedmeter system functionality can be very important in modern farmingpractices to obtain profitability. Some efforts have been made topressurize the seed meter housing interior to deliver the seeds out ofthe seed meter under positive pressure to increase seed speed leaving aseed tube. This can be challenging to control, especially in pneumaticseed meters that have vacuum and/or positive pressure states within theseed meter housing. Other efforts have been made to use flighted beltsand brush belts to accelerate seeds to ground speed, as other effortsare rather complex and have numerous moving parts that can wear overtime, which can reduce system performance.

SUMMARY OF THE INVENTION

The present invention is directed to a pneumatic seed delivery system ofa planter which improves the precision capabilities of the planter byusing high pressure air to accelerate seeds to match ground speed whenplanting. The high pressure air delivery may also continuouslypneumatically clear dust, debris, and/or other potential obstructionsout of the seed tube to improve seed delivery characteristics of theseed tube.

According to one aspect of the invention, the pneumatic seed deliverysystem may receive singulated seeds from a seed meter at each row unitand pneumatically adjust the delivery speed of the seeds to match theground speed of the planter or the particular row unit of the planter.This may minimize seed tumble of the seeds in the seed trench which mayimprove consistency of spacing distances between the seeds, which mayimprove yields.

According to one aspect of the invention, the pneumatic seed deliverysystem may include a pneumatic device such as an air conveyor or airamplifier that merges a primary airflow with a controllable supplementalairflow to provide a correspondingly controllable combined airflow. Thecombined airflow carries and accelerates singulated seeds from a seedmeter so that the seeds can be released with a rearward horizontal seedvelocity component that approximates a forward ground speed of theplanter to reduce seed tumble and improve spacing.

According to another aspect of the invention, a pneumatic seed deliverysystem is provided for use with a planter having multiple row units anda seed meter to singulate seeds at each row unit. The pneumatic seeddelivery system includes a pneumatic speed adjusting arrangementconfigured for controlling delivery velocity of seeds that are releasedfrom a release location of a seed meter of a planter for delivery ontoan agricultural field so that a horizontal seed velocity component ofthe delivery velocity of the seeds matches a ground speed of theplanter. The pneumatic speed adjusting arrangement may include an airaccelerator arranged downstream of the release location of the seedmeter. The air accelerator may deliver a supplemental airflow forcontrolling delivery velocity of the seeds downstream of the releaselocation of the seed meter to define an adjusted seed velocity. A seedtube has a seed tube outlet arranged downstream of the air acceleratorfor releasing seeds traveling at the adjusted seed velocity toward theagricultural field.

According to another aspect of the invention, the air acceleratorincludes an accelerator body that defines an interior and has anaccelerator inlet at a first end toward the seed meter. An acceleratoroutlet is arranged at a second end toward the seed tube. A primarypassage may extend longitudinally through the accelerator interior fromthe inlet of the accelerator body to the outlet of the accelerator body.The primary passage may direct a primary airflow to flow along with theseed through the accelerator body. At least one supplemental passage mayconnect to the primary passage for delivering the supplemental airflowtoward the primary airflow within the primary passage. The supplementalairflow may be combined with the primary airflow to provide a combinedairflow that flows out of the accelerator outlet to deliver the seedinto the seed tube.

According to another aspect of the invention, the air accelerator mayinclude an air conveyor. The air conveyor may have at least one portthat defines the supplemental passage(s). The port(s) may extendangularly inward toward and connect to the primary passage and extenddownstream toward the accelerator outlet. Multiple ports may becircumferentially spaced from each other about the accelerator body. Adistribution chamber may be defined within the accelerator body that isconcentrically spaced outwardly of the primary passage. The distributionchamber may receive the supplemental airflow and distribute thesupplemental airflow for delivery through the multiple ports.

According to another aspect of the invention, the air accelerator mayinclude an air amplifier having a port(s), such as a ring-shaped portthat defines the supplemental passage(s) and that extendscircumferentially about and radially inward toward the primary passage.A distribution chamber that is concentrically spaced outwardly of theprimary passage may receive the supplemental airflow and distribute thesupplemental airflow for delivery through the ring-shaped port.

According to another aspect of the invention, the air accelerator isarranged between the seed meter and the seed tube. The accelerator bodymay be arranged at least partially within the seed meter outlet. The airaccelerator may include an inlet tube arranged within the seed meteroutlet for receiving the primary airflow and the seed. An outlet tubemay be arranged within the seed tube for delivering the combined airflowand the seed into the seed tube.

According to another aspect of the invention, a planter is provided fordelivering seed at a pneumatically controlled seed delivery velocityonto an agricultural field. The planter includes a frame that supportsmultiple row units. A seed meter is arranged at each row unit tosingulate seeds. A seed tube receives the singulated seeds from the seedmeter for delivery onto an agricultural field. An air accelerator isarranged to receive the singulated seeds from the seed meter fordelivery into the seed tube at an adjusted seed velocity. The airaccelerator has a first inlet configured to receive a primary airflowand the singulated seeds from the seed meter. A second inlet of the airaccelerator is configured to receive a supplemental airflow that can becontrolled for adjusting the adjusted seed velocity. An outlet of theair accelerator is configured to release the singulated seeds within acombined airflow defined by a combination of the primary airflow and thesupplemental airflow into the seed tube at the adjusted velocity.Controlling the combined airflow by way of the supplemental airflowallows for controlling the adjusted seed velocity so that a rearwardhorizontal seed velocity component approximates a forward ground speedof the planter.

According to another aspect of the invention, a method of row-cropplanting is provided that pneumatically controls a horizontal seedvelocity component of seeds leaving a seed tube. A ground speed ismonitored that corresponds to a velocity of a planter relative to anagricultural field. Seeds are individually conveyed through a seed meterof the planter with a seed disk for row-crop planting of theagricultural field. The seeds are released from a release locationwithin the seed meter toward a seed tube that has a seed tube outlet forreleasing seeds toward the agricultural field. An in-tube seed velocitythat corresponds to a velocity of the seeds traveling through the seedtube is determined. Supplemental airflow is introduced downstream of therelease location within the seed meter for influencing the in-tube seedvelocity. The supplemental airflow is adjusted to adjust a seed deliveryvelocity that corresponds to a velocity of the seeds exiting the seedtube outlet based on values of the ground speed and the in-tube seedvelocity.

According to another aspect of the invention, a horizontal seed velocitycomponent is determined that corresponds to a horizontal velocity of theseeds exiting the seed tube outlet. The supplemental airflow may beadjusted based at least in part on the horizontal seed velocitycomponent, and the supplemental airflow may be adjusted to attenuate adifference between the horizontal seed velocity component and the groundspeed.

According to another aspect of the invention, the supplemental airflowmay be introduced through an air accelerator. The air accelerator mayreceive the supplemental airflow and deliver the supplemental airflowinto the seed tube. Adjusting the supplemental airflow may includeadjusting a pressure of the supplemental airflow received by and/ordelivered into an interior of the air accelerator.

Other aspects, objects, features, and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription and accompanying drawings. It should be understood, however,that the detailed description and specific examples, while indicatingpreferred embodiments of the present invention, are given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE FIGURES

Preferred exemplary embodiments of the invention are illustrated in theaccompanying drawings in which like reference numerals represent likeparts throughout.

In the drawings:

FIG. 1 is an isometric representation of a tractor pulling a planterthat incorporates a pneumatic seed delivery system in accordance withthe present invention;

FIG. 2 is a side elevational view of a portion of a row unit of theplanter of FIG. 1 incorporating the pneumatic seed delivery system ofthe present invention;

FIG. 3 is another side elevational view of a portion of a row unit ofthe planter of FIG. 1 incorporating the pneumatic seed delivery systemof the present invention;

FIG. 4 is another side elevational view of a portion of a row unit ofthe planter of FIG. 1 incorporating a variant of the pneumatic seeddelivery system of FIG. 3;

FIG. 5 is a simplified cross-sectional view of an air accelerator of thepneumatic seed delivery system of the present invention;

FIG. 6 is a simplified cross-sectional view of a variant of the airaccelerator FIG. 5; and

FIG. 7 is a flowchart of a use procedure of a pneumatic seed deliverysystem in accordance with the present invention.

DETAILED DESCRIPTION

Referring now to the drawings and specifically to FIG. 1, a pneumaticseed delivery system is shown as system 5 for improving plantingprecision capabilities by using high pressure air to accelerate seeds tomatch ground speed when planting and which may simultaneously providesufficient airflow through a seed tube to continuously pneumaticallyclear dust, debris, and/or other potential obstructions out of the seedtube to improve seed delivery characteristics of the seed tube.

System(s) 5 is incorporated on planter 7, which may be one of the EARLYRISER® series planters available from Case IH and is typically pulled bya traction device such as a tractor 9. A frame 11 of the planter 7supports multiple row units 13 that are substantially identical. Eachrow unit 13 includes various support, metering, and ground-engagingcomponents. These may include a sub-frame that is connected to the frame11 of the planter 7 by way of a parallel linkage system and furrowopening and closing mechanisms toward front and back ends of the rowunit 13. The opening and closing mechanisms may include opener disks andclosing disks, respectively, or other ground-engaging tools for openingand closing a furrow. Each row unit 13 may include a gauge wheelconfigured for adjusting furrow depth by limiting soil penetration ofthe furrow-opening mechanism while creating the furrow, and a presswheel may be arranged to roll over the closed furrow and to further firmthe soil over the seed to promote favorable seed-to-soil contact.

Still referring to FIG. 1, seed 17 is held in a seed storage systemshown here as a bulk seed storage system represented as bulk storagesystem 19. Bulk storage system 19 is shown here as a central bulkstorage system with at least one bulk fill hopper 21, shown here ashaving two central bulk fill hoppers 21 supported by the frame 11 of theplanter 7, remote from the row units 13. Each bulk fill hopper 21 has acompartment 23 for storing the seed 17. A seed conveyance system (notlabeled) may pneumatically deliver seed 17 from the bulk storage system19 to the row units 13, such as into an on-row seed storage system 25that may include mini-hoppers or other compartments. It is understoodthat the bulk storage system 19 can be configured with at least someon-row bulk storage at the row units 13 themselves, such as by way ofmanual-fill on-row bulk storage compartments (not shown) that do notpneumatically receive seed 17 from a remote bulk fill hopper 21.

Referring now to FIG. 2, at each row unit 13, seed 17 is delivered fromon-row seed storage system 25 into seed meter 27 that singulates theseed 17 and delivers the singulated seed 17 toward the agriculturalfield. Seed meter 27 can be a purely mechanical-type seed meter 27 or apneumatic seed meter 27. Each seed meter 27 includes a seed meterhousing 29 with first and second side portions or left and right coversthat connect to each other at their peripheries to define an enclosureto collectively surround a housing cavity in which seed disk 31 is atleast partially arranged for rotation. Although seed disk 31 is shown inFIG. 2 as entirely enclosed within seed meter housing 29 and its housingcavity, it is understood that at least a portion of seed disk 31 mayextend out of the seed meter housing 29 and its housing cavity. Othercomponents may be arranged within the housing cavity, such as variousseals that engage seed disk 31 to provide vacuum shut-off or positivepressure isolation and a seed singulator that is configured to inhibitmore than one seed from being discharged from the seed meter 27 per seeddischarge event. A brush assembly may be arranged within the housingcavity to provide a barrier that retains the seed 17 inside the housingcavity instead of, for example, spilling out of the seed meter 27without being carried by seed disk 31.

Still referring to FIG. 2, seed meter 27 is shown here as a pneumaticvacuum-type meter with vacuum inlet 33 at one side or meter cover ofseed meter housing 29 that is connected to a vacuum hose that appliesvacuum pressure from a vacuum pump or other vacuum source of a primaryairflow system 35 to pull seed 17 into the seed pockets of seed disk 31.Pneumatic positive pressure-type seed meters 27 (not shown) are operablyconnected through a pressurized air inlet (not shown) to the primaryairflow system 35 to provide a positive airflow and a correspondingpositive pressure at the seed side of the seed disk 31 within the seedmeter 27, whereby seeds from the seed pool are pushed and held againstthe seed disk 31, such as within the seed pockets, by positive pressure.A seed inlet (not shown) is provided at the side or meter cover of seedmeter housing 29 and defines a passage that receives seed 17 from on-rowstorage system 25 into a seed pool within seed meter 27. The seeds inthe seed pool are exposed to the seed disk 31, which picks up andsingulates the seeds using seed pockets or fingers from the seed pool.This is done by rotating seed disk 31 to move at least a surface of theseed disk 31 through the seed pool inside of seed meter 27. Rotation ofseed disk 31 is accomplished by way of a seed disk drive system. Theseed disk drive system may include, for example, various electric orhydraulic motors, drive shafts, chains and belts, clutches, peg-and-holedrive systems, and/or other arrangements such as a directly drivenarrangement in which a motor directly drives the seed disk 31 at its hubor periphery. After the individual seeds are conveyed through the seedmeter 27, the seeds are released from the seed disk 31 at releaselocation 37 inside seed meter 27 and exit seed meter housing 29 throughits seed meter outlet 39.

Still referring to FIG. 2, pneumatic seed delivery system 41 receivesseeds from seed meter outlet 39 and uses pneumatic pressure to adjustseed delivery speed or velocity to match ground speed when planting.Pneumatic seed delivery system 41 includes seed tube 43 and pneumaticseed speed adjusting arrangement 45. Seed tube 43 defines an enclosedpassageway within a seed tube body that may be defined by interconnectedseed tube walls that provide a seed tube inlet 43 a connected to orotherwise arranged downstream of seed meter outlet 39. Seed tube outlet43 b has an opening through which seed 17 is released from seed tube 43,exiting toward the agricultural field for row-crop planting. Pneumaticseed speed adjusting arrangement 45 is configured for pneumaticallyadjusting the speed of seed 17 downstream of seed meter 27, defining anadjusted seed velocity. Pneumatic seed speed adjusting arrangement 45includes air pressure system 47 which may include an air compressor 49that provides compressed air to a pneumatic device shown here as airaccelerator 51. Air accelerator 51 may be, for example, an air conveyor53 as shown in FIG. 5 or an air amplifier 55 as shown in FIG. 6,explained in greater detail elsewhere. Regardless of the particularconfiguration of air accelerator 51, pneumatic seed delivery system 41determines the velocity of seeds traveling through seed tube 43 andpneumatically influences the seed velocity to adjust a seed deliveryspeed to match ground speed when planting. Seed velocity sensor system57 may be used to directly or indirectly measure or determine seedvelocity. Seed velocity sensor system 57 is shown here with opticalsensor 59 and light source 61 that cooperate to detect disruptions oflight transmission from light source 61 to optical sensor 59 when seed17 passes between light source 61 and optical sensor 59. It isunderstood that seed velocity sensor system 57 may have non-opticalsensors for detecting seeds and seed velocity, directly or indirectly.Seed velocity sensor system 57 may instead or further detect airflowcharacteristics through seed tube 43, such as by way of a flow sensor(s)to detect airflow velocity. Such flow sensor(s) may include venturi-typeflow sensors, pitot tube-type flow sensor, and/or anemometers arrangedfor detecting airflow velocity through seed tube 43. The sensor(s) fordetermining airspeed may also be a static pressure sensor mountedoutside of seed tube 43 and arranged to detect pressure within seed tube43 through a pinhole in a wall of seed tube 43 so as to not impede seeddelivery through seed tube 43. Signals from the seed velocity sensorsystem 57 are used by control system 65 to directly or indirectlydetermine the velocity of the seed 17 traveling through seed tube 43 asan in-tube seed velocity and pneumatically adjust the speed of seed 17traveling through seed tube 43 to an adjusted seed velocity. It isunderstood that for indirectly determining seed velocity, instead ofusing static pressure along seed tube 43 wall, supplied air pressure ofthe supplemental airflow 95 may be used as a correlation for determiningseed velocity based on empirical measurements. In this way, indirectmeasurements such as detected air pressure of supplemental airflow 95 orstatic pressure at a wall of seed tube 43 can be used with lookup tablesor an algorithm that correlates the detected pressure(s) with a seedvelocity. The lookup tables or algorithm may further consider otherparameters such as seed type and seed size that may be entered by theoperator or pre-entered by a supplier and stored in memory of controlsystem 65 when determining seed velocity as a function of detectedpressure. As explained in more detail elsewhere, the adjusted seedvelocity is controlled to provide at the seed tube exit, a horizontalseed velocity component to correspond to ground speed of planter 7, butin the opposite direction so that seeds fall substantially verticallyfrom seed tube 43 with substantially no horizontal travel component withrespect to the ground.

Still referring to FIG. 2, control system 65 includes tractor controlsystem 67 and planter control system 69 that operably communicate witheach other, for example, by way of an ISOBUS connection, forcoordinating controls of tractor 9 (FIG. 1) and planter 7 (FIG. 1),including pneumatically controlling delivery speed of seed 17 throughseed tube 43. Tractor control system 67 is shown having a tractorcontroller 71 and power supply 73, and planter control system 69 isshown having a planter controller 75, pneumatic seed delivery systemcontroller 77, and power supply 79. Each of the tractor, planter, andpneumatic seed delivery system controllers 71, 75, 77 can include anindustrial computer or, e.g., a programmable logic controller (PLC),along with corresponding software and suitable memory for storing suchsoftware and hardware including interconnecting conductors for power andsignal transmission for controlling respective electronic,electro-mechanical, hydraulic, and pneumatic components of the tractor 9and planter 7. Tractor controller 71 is configured for controlling thefunctions of the tractor 9 by monitoring and controlling, e.g.,steering, speed, braking, shifting, and other operations of the tractor,which may include controlling various GPS steering or other GPS-relatedsystems, transmission, engine, hydraulic, and/or other systems of thetractor 9. A tractor interface system 81 is operably connected to thetractor control system 67 and includes a monitor and various inputdevices to allow an operator to see the statuses and to control variousoperations of the tractor 9 from within the cab of the tractor 9. Thetractor interface system 81 may be a MultiControl Armrest™ consoleavailable for use with the Maxxum™ series tractors from Case IH.

Still referring to FIG. 2, planter control system 69, for example, byway of pneumatic seed delivery system controller 77, controls airpressure system 47 and/or air accelerator 51 to increase or decreasepressure, volume, and/or flow rate and therefore airflow velocity tocontrol the seed travel velocity in seed tube 43. This may includecontrolling air compressor 49 to deliver compressed air to airaccelerator 51 at a pressure that allows air accelerator 51 toaccelerate the seed 17 to match ground speed of planter 7, but in anopposite direction. In addition to controlling air compressor 49,pneumatic seed delivery system controller 77 may control a regulatorsuch as an electronically controlled regulator shown here as regulator83 that is arranged between air compressor 49 and air accelerator 51 tocontrol the pressure or other flow characteristics at which compressedair from air compressor 49 is delivered to air accelerator 51. It isunderstood that regulator 83 may be integrated into air accelerator 51so that the adjustment of air pressure may be accomplished in airaccelerator 51 itself.

Referring now to FIG. 3, control system 65 controls pneumatic seeddelivery system 41 to adjust delivery of high pressure air to accelerateseeds to match ground speed when planting, with ground speedcorresponding to the travel speed of planter 7 (FIG. 1) and tractor 9(FIG. 1). Travel direction and ground speed of planter 7 (FIG. 1) andtractor 9 (FIG. 1) are represented here as a dashed-arrow ground speed85, shown facing to the left from seed meter 27. Pneumatic seed deliverysystem 41 may incorporate multiple airflows or airflow components, atleast one of which is adjustable, to control delivery velocity of theseed 17 from seed tube 43. The multiple airflows include a first airflowas a primary airflow, which may be a seed meter-exiting airflowdepending on the configuration of seed meter 27, represented asdownwardly facing dashed arrows 87. It is understood that if seed meter27 is a vacuum seed meter, primary airflow 87 may not originate frominside the seed meter 27, but may be an induced downdraft from airpressure system 47 or vented from the ambient. If primary airflow 87 isa downdraft induced downstream of a vacuum seed meter 27 housing cavity,then an air accelerator 51 support junction such as a junction betweenair accelerator 51 and seed meter 27 may be pneumatically sealed. Thisprevents or reduces leakage of the induced downdraft and correspondinglyreduces updraft at the seed release chamber or seed release location 37.As another example, air accelerator 51 may not be pneumatically sealedat its junction with seed meter 27 but air vents may be providedimmediately above air accelerator 51, in which case seeds 17 may fallthrough a slight updraft before reaching primary airflow 87 of airaccelerator 51. Regardless, the primary airflow 87 corresponds to airthat flows, is vented to reduce negative static pressure at seed releaselocation 37, or is induced under pressure as a downdraft that isdownstream of seed release location 37 of seed meter 27, into a firstinlet shown as a seed/air inlet or accelerator inlet 91 of airaccelerator 51 that faces toward seed meter 27. Accelerator inlet 91 isconfigured to receive both seed 17 and air from seed meter 27, such asfrom seed meter outlet 39. Air from seed meter outlet 39 can bedelivered under positive pressure toward air accelerator 51, if seedmeter 27 is a positive pressure seed meter. As another example, airwithin seed meter outlet 39 may be at ambient pressure, if the seedmeter outlet 39 and/or release location 37 is vented to outside air. Or,in the case of a vacuum seed meter 27, the air within the seed meteroutlet 39 may be at a slightly negative static pressure with respect toambient pressure. Regardless, a low pressure zone 93 may be definedimmediately upstream of the accelerator inlet 91 that enhances drawingair and seed 17 into air accelerator 51 through accelerator inlet 91.The multiple airflows of pneumatic seed delivery system 41 include asecond airflow as an auxiliary or supplemental airflow represented asright-facing solid-arrows 95 from air pressure system 47. Supplementalairflow 95 is produced by air pressure system 47 and delivered to airaccelerator 51 through a conduit, represented here as air line 97. Airline 97 connects air pressure system 47 to a second inlet of airaccelerator 51, shown as pressurized air inlet 98. Inlet air pressuresensor 99 is shown at the air inlet 98 arranged to detect an inletpressure value for use by control system 65 in controlling air pressuresystem 47. It is understood that air pressure may be detected elsewherein the pneumatic seed delivery system 41 for controlling seed deliveryspeed.

Still referring to FIG. 3, control system 65 controls the air pressuresystem 47 to influence characteristics of supplemental airflow 95, suchas pressure and/or velocity, as explained in greater detail elsewhere.Supplemental airflow 95 combines with primary airflow 87 within airaccelerator 51 to provide a combined airflow, represented as downwardlyfacing solid-arrows 101 extending from air accelerator 51. Combinedairflow 101 exits an outlet of air accelerator 51, shown here ascombined airflow outlet 103 that faces away from seed meter 27. Combinedairflow 101 has a greater velocity than primary airflow 87 so thatcombined airflow 101 accelerates the travel speed of seed 17 carried bycombined airflow 101 through seed tube 43. By controlling air pressuresystem 47 to adjust pressure and/or velocity of supplemental airflow 95,control system 65 can correspondingly adjust pressure and/or velocity ofcombined airflow 101 to influence travel speed of seed 17 travelingthrough seed tube 43. In this way, control system 65 is able to adjustdelivery velocity of seed 17 out of the seed tube 43. Seed deliverytravel path and velocity are represented as an angled dashed arrow 105at which seed 17 exits seed tube outlet 43 b as guided by the seed tube43 and entrained in combined airflow 101 within seed tube 43. Seeddelivery velocity 105 has vertical and horizontal vector components,shown here as vertical and horizontal seed velocity components 107, 109with dashed arrows that face downwardly and to the right, respectively.With the rearward horizontal seed velocity component 109 in the oppositedirection as the forward travel of planter 7 (FIG. 1) and tractor 9(FIG. 1), control system 65 adjusts the horizontal seed velocitycomponent 109 to substantially match the rearward horizontal seedvelocity component 109 to the forward travel speed 85. This reduceshorizontal rolling or bouncing in a seed trench or on the field thatwould otherwise be attributable to forward or rearward horizontalvelocity components or movement of seed 17 during seed delivery towardthe field.

Referring now to FIG. 4, air accelerator 51 is shown here withaccelerator body 113 that defines main body segment 115. Acceleratormain body segment 115 is generally cylindrical with a circumferentialsidewall 117 that has threaded port 119 that defines pressurized airinlet 98. Inlet tube 121 extends upwardly from and is shown with asmaller diameter than an upper end of accelerator main body segment 115and defines the accelerator inlet 91. A passage extends through theinlet tube 121 into an interior space of accelerator main body segment115, shown as accelerator interior 123. Outlet tube 125 extendsdownwardly from and is shown with a smaller diameter than a lower end ofaccelerator main body segment 115 and defines the combined airflowoutlet 103. A passage extends through the outlet tube 121, fromaccelerator interior 123 into an interior space of seed tube 43, shownhere as seed tube interior 127. Front segments of inlet and outlet tubes121, 125 are shown respectively abutting or adjacent inwardly-facingsurfaces of seed meter outlet front wall 129 and seed tube front wall131. A front segment of air accelerator 51 is shown extending beyondseed meter outlet and seed tube front walls 129, 131, which may extendthrough an opening 133 in seed meter outlet front wall 129.

Referring now to FIG. 5, air accelerator 51 is shown here as an airconveyor 53 and has a throat shown as intermediate tube segment 135 thatextends through the accelerator interior 123, between inlet and outlettubes 121, 125. Circumferential sidewall 117 is spaced concentricallyoutward from intermediate tube segment 135, defining an annular pressurechamber or distribution chamber 137 of air conveyor 53 that distributesthe pressurized air from the pressurized air inlet 98 for release intoaccelerator interior 123 at different locations. Distribution chamber137 is defined between outer and inner pressure chamber walls 139, 141defined by inwardly-facing and outwardly-facing surfaces ofcircumferential sidewall 117 and intermediate tube segment 135. Upperpressure chamber wall 143 is defined by a downwardly-facing surface of ashoulder that connects circumferential sidewall 117 to inlet tube 121.Lower pressure chamber wall 145 is defined by an upwardly-slanting andinwardly-facing surface of a shoulder that connects circumferentialsidewall 117 to outlet tube 125. Bores shown as ports 147 arecircumferentially spaced from each other and extend through lowerpressure chamber wall 145 to deliver the supplemental airflow 95angularly from distribution chamber 137 into the accelerator interior123. Mixing chamber 149 is defined between intermediate tube segment 135and conveyor outlet tube 125, at and downstream of ports 147. Mixingchamber 149 is shown here with an upper segment that tapers outwardly toa larger diameter than that of the intermediate tube segment 135 and alower segment that tapers inwardly, reducing its diameter toward outlettube 125.

Still referring to FIG. 5, primary airflow 87 and supplemental airflow95 combine with each other in mixing chamber 149 to provide combinedairflow 101, with primary airflow 87 flowing along a generally straightline path through a columnar axial passage of accelerator interior 123.Supplemental airflow 95 is released through ports 147 in a concentricpattern around the axial passage of accelerator interior 123, angularlyinward toward primary airflow 87 and downstream through mixing chamber149. This accelerates primary airflow 87 at mixing chamber 149 andlowers the pressure at low pressure zone 93 (FIG. 4) to help drawadditional volumes of air in the primary airflow 87 and seed 17 into airconveyor 53 to be accelerated by supplemental airflow 95 to establishcombined airflow 101. Combined airflow 101 has a greater pressure and/orvelocity than that of primary airflow 87 and can be adjusted by controlsystem 65 (FIG. 3) controlling the supplemental airflow 95, forcontrolling the velocity of seed 17 (FIG. 3) leaving seed tube 43 (FIG.3). In this way, a primary passage 151 extends longitudinally throughaccelerator body 113 for directing flow of primary airflow 87 and seed17 toward mixing chamber 149. Primary passage 151 may be defined by therespective inner surfaces of inlet and outlet tubes 121, 125 andintermediate tube segment 135. At least one supplemental passage 153,represented here as port(s) 147, connects to primary passage 151 fordelivering the supplemental airflow 95 toward the primary airflow 87 tocontrol airflow characteristics such as velocity of the combined airflow101.

Referring now to FIG. 6, air accelerator 51 is shown here as an airamplifier 55. Air amplifier 55 is similar to air conveyor 53 in FIG. 5,so the description of air conveyor 53 in FIG. 5 is applicable here withrespect to air amplifier 55 in FIG. 6. However, air amplifier 55 differsfrom air conveyor 53 in the following ways. Instead of port(s) 147 beingdiscrete bores that face angularly downstream from a downstream end ofdistribution chamber 137, like in air conveyor 53 (FIG. 5), port 147 ofair amplifier 55 is shown as a ring-shaped concentric opening that facesgenerally radially inward into axial passage of accelerator interior 123from an upstream end of distribution chamber 137. As shown in FIG. 6,supplemental airflow 95 may flow from the ring-shaped port 147 along anupside down U-shaped flow path, upwardly out of annular distributionchamber 137, radially inward through port 147, then downwardly towardoutlet tube 125. In this configuration, supplemental airflow 95 exitsport 147 and flows to follow the contours and surface(s) of intermediatetube segment 135 by way of a Coanda effect or profile so that lessmixing may occur in the mixing chamber 149 in the air amplifier 55 (FIG.6) compared to air conveyor 53 (FIG. 5). Instead, at and downstream ofmixing chamber 149 in the air amplifier 55, supplemental airflow 95 mayflow at least momentarily longitudinally and concentrically around theprimary airflow 87. This accelerates primary airflow 87 and lowers thepressure at low pressure zone 93 (FIG. 4) that may also extend into theinlet tube 121 to help draw additional volumes of air in the primaryairflow 87 and seed 17 into air amplifier 55 to be accelerated bysupplemental airflow 95 to establish combined airflow 101. Like with airconveyor 53 (FIG. 5), air amplifier 55 is controlled by control system65 (FIG. 3) to adjust the supplemental airflow 95 for controlling thevelocity of seed 17 (FIG. 3) leaving seed tube 43 (FIG. 3).

Referring now to FIG. 7 and further referring to components of FIGS.1-3, system 5 may be controlled as represented by procedure 201 ingenerally the following way to automatically adjust the seed exitvelocity of seed 17 from the seed tube 43. The procedure allows therearward horizontal seed velocity component 109 of seed 17 released fromseed tube 43 to substantially match the forward ground speed 85 of theplanter 7 or a particular row unit 13. This provides a negligiblehorizontal velocity or substantially zero-mph horizontal speed of seed17 released from seed tube 43. Control system 65 determines ground speedas represented at block 203. This may include tractor controller 71detecting travel speed by way of a speed sensor and/or GPSspeed-detecting features. Speed may also be determined using a wheelspeed sensor of planter 7. As represented at block 205, control system65 determines the horizontal seed velocity component 109 of seed 17delivered out of seed tube 43. This may include planter controller 75 orpneumatic seed delivery system controller 77 determining a velocity ofseed 17 traveling through seed tube 43 with seed velocity sensor system57, which may correspond to the seed delivery velocity 105. The value ofseed delivery velocity 105 is used by the planter controller 75 orpneumatic seed delivery system controller 77 to determine the horizontalseed velocity component 109 by, for example, calculation or reference toa lookup table of stored values. As represented at block 207, acomparison is made between the horizontal seed velocity component andthe ground speed, which may include an evaluation of a threshold value.The comparison may be done by way of a comparison engine implemented insoftware of the planter controller 75 or pneumatic seed delivery systemcontroller 77. The threshold value(s) may correspond to a percentage orvelocity value(s), for example, plus or minus ten percent, plus or minustwo miles per hour, or threshold values that collectively define atarget range. If the horizontal seed velocity component is within thetarget range and thus closer to the ground speed than the plus and minusthreshold values, then control system 65 continues to determine groundspeed at block 203, determine the horizontal seed velocity component atblock 205, and make the velocity comparison at block 207.

Still referring to FIG. 7 with further reference to components of FIGS.2 and 3, if, at the velocity comparison at block 207, the comparisonshows that the horizontal seed velocity component is outside of thetarget range and therefore greater or less than the plus or minus groundspeed threshold values, then the control system 65 commands anadjustment or varying of air pressure, as represented at block 209. Thismay be done by control system 65 using signals from the inlet airpressure sensors 99 to determine current inlet pressure at air inlet 98and executing a correction by controlling air pressure system 47 toincrease or decrease inlet air pressure to attenuate a differencebetween the horizontal seed velocity component 109 and the ground speed85. For example, pneumatic seed delivery system controller 77 maycontrol air compressor 49 to operate at a higher or lower pressure ormay control regulator 83 to deliver higher or lower pressure air to airaccelerator 51.

Referring now to FIG. 7 with further reference to components of FIG. 5,if air accelerator 51 is an air conveyor 53, then increasing inlet airpressure at block 209 increases the pressure and velocity ofsupplemental airflow 95 delivered angularly through the discrete ports147 to increase velocity of combined airflow 101 and correspondinglyincrease velocity of seed 17. Decreasing inlet air pressure at block 209decreases the pressure and velocity of supplemental airflow 95 deliveredangularly through the discrete ports 147 to decrease velocity ofcombined airflow 101 and correspondingly decrease velocity of seed 17.

Referring now to FIG. 7 with further reference to components of FIG. 6,if air accelerator 51 is an air amplifier 55, then increasing inlet airpressure at block 209 increases the pressure and velocity ofsupplemental airflow 95 delivered concentrically along intermediate tubesegment 135 through the ring-shaped port 147 to increase velocity ofcombined airflow 101 and correspondingly increase velocity of seed 17.Decreasing inlet air pressure at block 209 decreases the pressure andvelocity of supplemental airflow 95 delivered concentrically alongintermediate tube segment 135 through the ring-shaped port 147 todecrease velocity of combined airflow 101 and correspondingly decreasevelocity of seed 17.

Many changes and modifications could be made to the invention withoutdeparting from the spirit thereof. The scope of these changes willbecome apparent from the appended claims.

We claim:
 1. A planter for delivering seed at a pneumatically controlledseed delivery velocity onto an agricultural field, the plantercomprising: a frame; multiple row units supported by the frame; a seedmeter arranged at each row unit to singulate seeds at each row unit; aseed tube receiving the singulated seeds from the seed meter fordelivery onto an agricultural field; an air accelerator arranged toreceive the singulated seeds from the seed meter for delivery into theseed tube and including, a first inlet configured to receive a primaryairflow and the singulated seeds from the seed meter; a second inletconfigured to receive a supplemental airflow that can be controlled foradjusting the pneumatically controlled seed delivery velocity; and anoutlet configured to release the singulated seeds within a combinedairflow defined by a combination of the primary airflow and thesupplemental airflow into the seed tube at an adjusted velocity.